This invention .relates to a special carton cooperative with compressed flexible duct to enable retention of the compressed duct and dispensing of controlled lengths of the duct from the carton.
Flexible convoluted duct has the capacity to be extended or compressed to various lengths. Such duct typically is constructed of a helical support member as of metal or plastic, and an enclosure jacket which normally surrounds and/or embeds the helical support. When the duct is axially compressed, the helical support has inherent resilient bias tending to return the duct back to its original length. Such duct is typically shipped in compressed condition in a carton. Opening of the carton can result in the compressed duct springing forth not unlike a jack-in-the-box without attachment to the box.
One technique for controlling extension of the duct from the carton is that set forth in U.S. Pat. No. 4,771,884, i.e., providing a restricted opening in the end of the carton, smaller than the duct diameter, to require the duct to be physically pulled through this smaller opening while successive portions of the duct are transversely constricted. Applying these tensile and deformation stresses to the duct is not always desirable.
Another construction for retaining the duct in the carton and allowing controlled lengths to be withdrawn is set forth in pending U.S. application Ser. No. 493,939, filed Mar. 15, 1990, and entitled Flexible Duct and Carton. This provides a breakout panel forming an opening in a side panel larger than the duct diameter, by enabling a portion of this panel to be pulled with a tucked end flap, separated along parallel side edges, and folded down around a crease spaced from the end of the carton.
U.S. Pat. No. 4,921,105 employs a side opening which folds about the card panel.